


Fire In Your Blood, And Also On The Floor

by Ren_What_Even



Category: Haikyuu!!
Genre: Child Death, Criminal Psychologist Student!Tsukishima, M/M, Serial Killer!Yamaguchi, kids killing kids basically, there's death in this
Language: English
Status: In-Progress
Published: 2016-11-24
Updated: 2018-02-18
Packaged: 2018-09-01 23:08:23
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 3,167
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8641858
Author URL: https://archiveofourown.org/users/Ren_What_Even/pseuds/Ren_What_Even
Summary: AU where Yamaguchi is a serial killer, and how he came to be that way.





	1. Chapter 1

**Author's Note:**

> Hello everyone! This is my first time writing Yamaguchi, or anything of this genre, ever, so appologies in advance if it's not very in character or seems unrealistic. This one-shot was inpired by @baraowl on tumblr, and the headcanons we exchanged with each other. Thank you for reading!  
> -R

The very first time Yamaguchi Tadashi had directly caused someone's death, he was five years old. It was a warm summer day, the sun beating down, but a gentle cool breeze preventing any real risk of heatstroke. At the time, the Yamaguchi family lived next door to the Somas, a lively family with two children, a wife and a husband, who also happened to work with Tadashi's father. The youngest Soma, Ryuuto, was a boisterous, talkative, but friendly boy, and was in Tadashi's class, so naturally they were friends. Since it was summer, the two families decided to take a road trip to the beach.

It really was lovely there; soft sandy beaches, the water cool and blue, and the sound of the ocean waves crashing in the distance. The two boys couldn't wait to get in the water, and after the hassle their mothers made of putting on sunscreen, they were both reminded: Do not go out too far, and be very careful of the undercurrent. After promising to take caution, the children ran out into the ocean, splashing each other and playing in the waist-deep waves.

"Hey, Tada-kun! Let's play a game!" Ryuuto suggested, his eyes gleaming in excitement. Tadashi smiled back and nodded. "Alright, what do you want to play?"  
"Let's see who can hold their breath underwater the longest, the loser has to buy the other ice cream!"

"Eh? But I didn't bring any money with me."

"Just ask your mother for money, then."

"Alright, but I'm gonna win!" Tadashi exclaimed, filled with determination. Ryuuto laughed in excitement and grinned. "We'll see about that."

Tadashi wasn't usually a competitive child, but something felt different this time. Maybe it was the prospect of ice cream, or another ulterior motive, but there was almost a burning feeling in his stomach. Tadashi didn't think much of it, and waited for Ryuuto to count to three before inhaling all the air his lungs could manage, and plunged into the water.

He was lucky that his mother packed goggles, Tadashi thought, as he marvelled in the sight of all the colourful rocks at the bottom, the sunlight filtering through the water. He wiped the front of his goggles. They were nice ones, his mother had bought them for him when he joined the swim team at his elementary school. The members of that team weren't nice, though, he thought, and by the end of the month he was begging his mother to let him quit the team, although he never told her why.

Looking at Ryuuto, his eyes squinted closed as he didn't have goggles, he felt himself start to run out of breath. He began to panic, as he didn't want to lose. He always lost the games that Ryuuto wanted to play, just once, he thought, just once it would be nice to win. And the only way to do that was to make sure that Ryuto ran out of breath first.

Without thinking, he swam over and pushed down on the boy's shoulders. This caught him by surprise, and his eyes opened wide in shock. He thrashed, hit Tadashi's hands and screamed, but no sound escaped, only bubbles. Just a little more, Tadashi thought, pushing down harder until Ryuuto stopped moving, his eyes closed.

  
_Ha!_ He thought, letting go of the boy's shoulders. He won! He got the ice cream! Tadashi stood up out of the water and pushed his goggles up. He was about to celebrate when a horrified scream cut through the air, and he saw his friend's mother running, panicked over to him, when he noticed that Ryuuto's body was floating beside him, face-down in the water. The mother picked his body up, and Tadashi noticed that his lips were blue. He blinked in a muddled haze as the panicking mother was drawing a crowd, and a lifeguard quickly ran over and took the boy, laid him down on the sand and began pressing on his chest.

"Tadashi!" He looked away to see his own mother now, running towards him, and grabbing him by the shoulders. "What happened?! What were you doing?!" He blinked at her before frowning and answering. "We were playing a game underwater, Mom."

"Someone call an ambulance, he still isn't breathing!" The lifeguard yelled, and because there was a hospital down the road, paramedics arrived shortly, with a stretcher and a mask and many other tools that Tadashi didn't know the purpose of. Before he could see what they were doing to his friend's body, his mother hugged him, her body shielding his view. "Don't look, Tadashi."

"Poor kid, must've gotten stuck in the undercurrent."

"Children these days, so reckless. The other one is lucky he didn't drown either." The crowd that formed around the scene began to murmur. He could vaguely hear other things being said by the paramedics, something he couldn't understand. All that registered was that after all of Ryuuto's games, he had finally won, all by himself. Tadashi buried his face in the crook of his mother's neck and smiled to himself, wondering when he was going to get that ice cream of his.  
\----------------------------------------------------------------------------------------------------------------------------

The second time Tadashi killed someone, it was on Halloween, when he was nearly eight years old. He'd gone as a ghost, complete with a white sheet draped over him, and small eye slits cut out for him to see. He was tagging along with a few of the neighbourhood kids that night, they were nice enough, but he didn't really feel as though he really clicked with any of them. Still, he chatted with them happily about how much candy they had already collected, which houses gave out the best candy, and which one they should go to next.

  
Those plans were halted suddenly when a larger figure stepped out from around the corner, smirking menacingly at them. It was Iijima Shougo, the neighbourhood bully. He was taller than them, and despite being only a first year in middle school, was already developing muscles. He held out a meaty hand to the group. "Hand over the candy, or someone gets hurt!" He demanded.

  
"We worked hard for this candy! Go get your own." Soma Takumi, coincidentally Ryuuto's younger brother, spat at the bully. After the beach incident, Takumi had stuck to Tadashi like glue, asking him to kick a soccer ball around, taking him to get ice cream, showing up early in the morning on weekends to watch cartoons with him. His mother had explained to him, carefully, as if she were trying to avoid hurting his feelings, that because Takumi didn't have his older brother anymore, Tadashi would have to take his place.

  
Takumi had silver hair, and a sharp attitude. Despite being a year younger than Tadashi, he was quick as a whip, and was good at hiding the fact that he was indeed, very afraid of the bully in front of them. With one hand he clutched his pillowcase, the other clutched the back of Tadashi's sheet.

"I didn't ask for lip, brat. Now hand it over, or you'll really be sorry." Takumi stayed fast, glaring fiercely at the bully. Iijima walked up slowly, and then, before anyone could react, punched Takumi right in the face. The younger child staggered back a little, before his eyes widened in alarm as blood began dripping out of his nose. "H-hey! He didn't do anything to you! Why can't you just leave us alone?!" Tadashi blurted without thinking.

  
He felt his legs shake as Iijima then grabbed him by the collar and threw him to the ground. His head collided with the cement and he felt a strange ringing in his ears and the muffled sound of footsteps running away.

  
"O-onii-chan! Are you okay?!" Takumi was kneeling beside Tadashi, hands fluttering over, but not quite touching him, as if the younger boy was afraid of hurting him anymore.

  
"Ah, yeah, I think so. Thanks, Takumi." He took the offered hand and was pulled up. "But they took the candy." Tadashi remarked, noticing the trail of candy leading away from where they were standing.

"Those jerks! Who do they think they are?! I worked so hard to get that candy too." Takumi spat, rubbing angrily at his eyes before tears could leak out. Something about that scene caused a reaction in Tadashi's stomach, a burning need for... something. He couldn't place it exactly, but he knew it had something to do with that bully, Iijima. He placed a hand on the younger boy's shoulder.

  
"Wait here, Takumi, I'll get it back for us." He reassured him. The silver-haired boy's eyes widened. "Onii-chan, don't! You'll get hurt again! And.. It'll be all my fault." His head lowered and his eyes were fixed on his shoes. "Don't worry, I'll try talking to him first. I'll make sure it won't come to violence."

  
Squaring his shoulders and throwing his sheet back over his head, he began walking in the direction of the bully.

  
It didn't take long for him to catch up, following the boy down a few streets and then into an abandoned alleyway, where the bully began dumping the candy out onto the ground, laughing as he began digging through the pilfered candy. Tadashi's eyes narrowed at the sight.

 _I'm sorry, Takumi._ He apologized in his mind. _I know Iijima, he'll never listen to reason._ He was about to move forward when his eyes landed on an object a few steps away from him, and the plan suddenly unraveled in his mind.

  
Iijima never saw it coming. With a quick swipe of his hand, the brick in Tadashi's hand connected with the back of the bully's head, causing him to cry out in pain. Quickly, Tadashi pulled out his sheet and threw it over the other's head, clapping a hand over the bully's mouth. The other hand wrapped around to pinch his nose.

  
He probably would've struggled more, if his head hadn't been bleeding, and at that moment, Tadashi's arm strength outmatched his feeble thrashing. Tadashi held him like that more another little while, until he could feel no movement coming from him. He released him and watched Iijima flop face-first onto the ground, his lips blue and his face pale. The bloody wound on the back of his head continued to leak blood slowly.

Tadashi's mind raced as he tried to busy himself with picking the candy up and putting it back in the pillowcase. Unlike last time, Tadashi understood what he had done. He'd killed the bully that had tormented him throughout elementary school. He'd killed his childhood best friend, Ryuuto. People who killed others were bad people, weren't they? That made him a bad person, didn't it? His hands began to tremble as the last piece of candy slipped out between his fingers.

  
No. Tadashi shut his eyes. _They_ were the bad people. Iijima deserved it, he was a bully. He'd always been mean to Tadashi, beating him up, hiding his shoes, filling his locker with garbage. He'd made life miserable for Tadashi. _Ryuuto..._ He paused for a moment, feeling the wave of guilt settle over him, the way it always did when he thought of his late childhood friend. Ryuuto was a show-off, he decided, picking the candy up again and tossing it into the pillowcase. Always making Tadashi feel like he wasn't good enough. With a nod to himself, he glanced at the body of Iijima Shougo. His corpse's legs were sticking out from behind the dumpster, so Tadashi nudged the body closer to the wall, the body wouldn't be seen at first glance by a passer-by anytime soon.

  
Finally, Tadashi took a deep breath, collected his sheet and the pillowcase full of candy, and ran back to find Takumi.

\----------------------------------------------------------------------------------------------------------------------------

The woman in the navy blue suit was thrashing quite violently, fortunately her head was still underwater, held there by Tadashi's vice grip around her neck. Her screams were contained inside the bathtub, air bubbles escaping but nothing else. Her legs were kicking, water splashing all over his clothes, but he didn't mind it as much as he used to. The rush of adrenaline he got from experiences like these were definitely worth coming up with excuses for Tsukishima about why his clothes were damp or why he sometimes had bruises and scratches on him, a direct result from his victims' struggling.

  
This woman in particular, Takeshi Minako, happened to be a politician. Nothing too big, she was a member of a particular political party that had been gaining popularity lately. Her platform, however, was incredibly bigoted, and overall despicable. Conversion therapy, further restrictions on homosexual relationships, and the repeal sex reassignment surgery were all on her agenda. His eyes narrowed in anger and his hands squeezed tighter around her neck.

 _Dissapear._ He thought, furious. _Dissapear off the face of the earth and burn in hell._ Takeshi gave one lash thrash, and then went still. Tadashi sighed a breath of relief. His hands were a bit sore from gripping so tightly, but the fire in his chest burned bright and hot, making him feel a bit lightheaded and energized. He sat back against the bathroom wall and stared at the body in the bathtub, her hand hanging out of it, limp.

  
Taking a deep breath, he stood, his bare feet sticking to the tile, before taking one more look at the body in the tub, and leaving. Putting his socks and shoes on, he locked the doorknob from the inside and closed the door. It had been so easy, following Takeshi into her apartment, she never locked the door behind her, he didn't even really need to remove his footwear to quiet his steps. He shook his head on the way out. She was an idiot, and surely her death was for the benefit of a lot of people, he reasoned with himself.

  
He felt the chilly cling of his wet t-shirt to his chest and started to think of ways to explain why his clothes were wet to Tsukishima. Maybe he ran into someone and they spilled their drink on him? He nodded his head to himself. That should work.

  
When he stepped outside the apartment building, he felt the cold raindrops touch his skin that fell from the now stormy sky. Tadashi looked up at the dark grey clouds and smirked. Even better.

\----------------------------------------------------------------------------------------------------------------------------

Two subway trips later and a long trek up the stairs, he finally unlocked the door to his and Tsukishima's apartment. "Tsukki! I'm back!" He called, but got no response. _He must still be in class._ He thought, stepping in, locking the door behind him, and placing his keys down on the table. He removed his shoes before heading to the bedroom to change out of his wet clothes. One warm shower and a clean pair of warm pyjamas later, Tadashi sat on the couch, wrapped in a fleece blanket on the couch, flipping through T.V. channels.

  
His face perked up as he heard the telltale sound of Tsukishima's irritation towards the door lock, having trouble opening it again. After a few moments of grumbling and the sound of the key turning in the lock several times, the door swung open and Tadashi's blond boyfriend walked in. "Kei! How was class?" The freckled boy greeted the blond with a smile, and got a kiss on the forehead in return.

  
"Not bad, had a test, took some notes. Kuroo managed to find me during lunch afterwards, the nuissance. He says hi, by the way." Kei flopped down on the couch, laying his head on Tadashi's lap and sighing in comfort. "I hate my morning classes. Why do I ever bother going to them that early?"

  
Tadashi chuckled gently and stroked his blond hair, feeling the strands run in between his fingers. The moment, however, was interrupted by a breaking news report, announcing the death of Takeshi Minako. Kei's eyes widened in surprise. "Holy shit." He whispered. "Someone actually killed her."

  
Tadashi hummed, somewhat absentmindedly, trying desperately to keep from smiling in delight.

\----------------------------------------------------------------------------------------------------------------------------

A few days later, Tadashi was in a somewhat similar situation, sitting on the couch, and watching a bunch of experts on the news discuss the, now confirmed, murder of Takeshi Minako. He jumped in surprise when he felt something cold come in contact with his neck. He looked up to see Kei holding a can of pop.

  
"We were talking about the case in class today." Tadashi took the can as the blond walked around the back of the couch and sat down next to him, eyes glued to the screen. "Oh, really?" He replied, cracking open the can and taking a sip.

  
"Yeah. The professor was talking about how it would probably be really tough to find any evidence, considering the water in the bathtub drained, and the prints they pulled from the floor and doorknobs were all smudged or there were too many layered over them since the murder to be distinguished."

  
"Do you think they'll be able to find out who did it?"

  
"Maybe, but it's pretty unlikely. It could've been someone hired to do it, they seemed to know what they were doing when they killed her. Plus, everyone knew about how shitty of a person she was, a lot of people would probably try to take credit for it anyways."

  
"Hmm. Makes sense."

  
Behind the rim of the can, Tadashi's grin widened.

\----------------------------------------------------------------------------------------------------------------------------

And that's all, folks! Gosh, I started this so long ago (March!!), can you find any differences in my writing style at all? I actually had to do research ([x](https://www.quora.com/From-what-can-fingerprints-be-lifted-and-from-what-cant-they-be-lifted)) on this, surprisingly. It was fun, though :) Once again, I'd like to credit this AU to [@baraowl](http://baraowl.tumblr.com/) on tumblr, I hope you liked it, Danalle! There's art of this as well! You can check it out here ([x](http://baraowl.tumblr.com/post/140075801564/mmmmmmm-i-dont-think-im-going-to-finish-this)). I'm also on tumblr, so if you'd like, you can check it out here ([x](http://setter-senpai.tumblr.com/)) Alright, that's everything. Thank you all so much for reading, I hope you enjoyed reading this as much as I enjoyed writing it. Have a nice day!  
-R


	2. Update!

**Summary for the Chapter:**

> Eyyo it's ya boi, back at it with more TsukkiYama murder times

Hello everyone! I know it's been a while but I'm back and writing the next part of this AU! I've got the bare bones written down, so now all that's left is to... Y'know, actually write it -.- I hope you'll be patient with me, though! I realised through writing this that this AU has a lot of room to explore with, and so much more world building than I previously thought. This whole idea was originally just a one-shot that I did for an artist because I loved [their au](http://baraowl.tumblr.com/search/serial+killer+yamaguchi) and the [headcanons we shared about it](http://baraowl.tumblr.com/search/setter-senpai). I've been sitting on this for about two years and I finally had a stroke of inspiration and quickly wrote down how I thought it could go down. 

So please be prepared for more content in the future! Thank you so much to everyone who commented and left kudos, you're all amazing!!

~Ren


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